Carbon and nitrogen stable isotope analyses were used to infer relative trophic structure and examine regional variation in trophic dynamics of fishes in the Florida Big Bend, an approximately 300 km stretch of relatively pristine coastline in the eastern Gulf Of Mexico that contains over 250,000 ha of seagrass. The Florida Big Bend is home to a diverse assemblage of fauna; and the ecosystem is regionally important through its support of robust fishing (recreational and commercial) and eco-tourism industries. Stable isotope analyses suggest assemblages of fishes in the Florida Big Bend are trophically diverse, with considerable isotopic overlap across many taxa. Patterns of trophic structure corroborated the results of similar studies of these and related taxa and in other seagrass ecosystems, and there appear to be multiple channels of primary production. Large elasmobranch fishes were most enriched in δ 15 N with values well above the teleost fishes sampled, while smaller and demersal elasmobranchs had δ 15 N signatures comparable to several species of predatory teleosts. Results of stable isotope analyses suggested high trophic redundancy and overlap in resource use among both teleost and elasmobranch fishes. Comparisons of regional stable isotope values revealed some spatial variability and indicated the southern Big Bend is isotopically distinct, suggesting a distinct regional faunal zone in this region, potentially due to greatly reduced river influence in the southern portion of the system.

中文翻译：

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由稳定同位素分析确定的大型亚热带海草生态系统（佛罗里达大弯）中的硬骨鱼和硬骨鱼的营养生态学

碳和氮稳定同位素分析用于推断相对营养结构并检查佛罗里达大弯鱼类营养动态的区域变化，佛罗里达大弯是墨西哥湾东部大约 300 公里的相对原始海岸线，包含超过 250,000 公顷的海草. 佛罗里达大弯是各种动物群的家园。生态系统通过支持强大的渔业（休闲和商业）和生态旅游产业而具有区域重要性。稳定同位素分析表明，佛罗里达大弯的鱼类组合在营养上是多样的，在许多分类群中有相当大的同位素重叠。营养结构的模式证实了对这些和相关分类群以及其他海草生态系统的类似研究的结果，并且似乎有多种初级生产渠道。大型硬骨鱼的 δ 15 N 含量最高，其值远高于采样的硬骨鱼，而较小的和底栖的硬骨鱼的 δ 15 N 特征可与几种捕食性硬骨鱼类相媲美。稳定同位素分析的结果表明，硬骨鱼类和硬骨鱼类在资源利用方面存在高度的营养冗余和重叠。区域稳定同位素值的比较揭示了一些空间变异性，并表明南大弯的同位素是不同的，这表明该区域有一个独特的区域动物区系，这可能是由于系统南部的河流影响大大减少。而较小和底层的 elasmobranchs 具有与几种捕食性硬骨鱼相当的 δ 15 N 特征。稳定同位素分析的结果表明，硬骨鱼类和硬骨鱼类在资源利用方面存在高度的营养冗余和重叠。区域稳定同位素值的比较揭示了一些空间变异性，并表明南大弯的同位素是不同的，这表明该区域有一个独特的区域动物区系，这可能是由于系统南部的河流影响大大减少。而较小和底层的 elasmobranchs 具有与几种捕食性硬骨鱼相当的 δ 15 N 特征。稳定同位素分析的结果表明，硬骨鱼类和硬骨鱼类在资源利用方面存在高度的营养冗余和重叠。区域稳定同位素值的比较揭示了一些空间变异性，并表明南大弯的同位素是不同的，这表明该区域有一个独特的区域动物区系，这可能是由于系统南部的河流影响大大减少。